F region
That portion of the ionosphere existing between approximately 160 and 400 km above the surface of the Earth, consisting of layers of increased free-electron density caused by the ionizing effect of solar radiation. Note 1: The F region reflects normal-incident frequencies at or below the critical frequency (approximately 10 MHz) and partially absorbs waves of higher frequency. Note 2: The F1 layer exists from about 160 to 250 km above the surface of the Earth and only during daylight hours. Though fairly regular in its characteristics, it is not observable everywhere or on all days. The principal reflecting layer during the summer for paths of 2,000 to 3,500 km is the F1 layer. The F1 layer has approximately 5 ´ 105 e/cm3 (free electrons per cubic centimeter) at noontime and minimum sunspot activity, and increases to roughly 2 ´ 106 e/cm3 during maximum sunspot activity. The density falls off to below 104 e/cm3 at night. Note 3: The F1 layer merges into the F2 layer at night. Note 4: The F2 layer exists from about 250 to 400 km above the surface of the Earth. The F2 layer is the principal reflecting layer for HF communications during both day and night. The horizon-limited distance for one-hop F2 propagation is usually around 4,000 km. The F2 layer has about 106 e/cm3. However, variations are usually large, irregular, and particularly pronounced during magnetic storms.
The Urban Dictionary Tee
Love the short mine says bih on it
this shit stays on during sex
Love it! Buyed it for my sister but I had to make it say her favorite anime 💀✨
LOVR THIS SHIRT OML SO CUTEEEEE😍😍😍
mine had gay on it. Instant sex.
I love my NIckIsBum T-Shirt, it is very comfortable.
used it as a cum rag
Great fit and soft material. Gave as gift. Big hit!
Great conversation piece! Plus I can never find anything with my name on it. This was a great find! Will definitely order more!!!!
Got exactly what I wanted.
Exactly what I expected, thanks!
I don't visit Urban Dictionary alit so I only recently saw they offered merch. I immediately started looking up words for potential Christmas gifts. Found the ideal gift for my brother & ordered a shirt. It arrived very quickly and I love it. It's exactly as pictured on the site and being able to customize it with his name makes it perfect. I only hope he loves it as much as I do. Will definitely keep Urban Dictionary in mind when I need to find a great gift.
i love my shirt i made it say sapnap cause yassssssssss
Best This is the best shirt I have ever gotten I love it and I definitly recomend it to any friend named Hailie
So cool to quickly be able to turn a trending phrase into wearable art!
it was really good i put dad with the def of tfu and lol
*clap* *clap* MEME REVIEW. this is so amazing, alexa play despacito 9001
Love this shirt. Got it for my brother for Christmas and I can’t wait for his reaction! Ordered size L and it seems maybe a little big? Thank you!
thankyou for all your kind reviews. For everyone complaining about the spelling we was high on the bezamine while writing it so fuck youuuuuu
I love it
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Size Guide
Measurements may vary by up to 2" (5 cm). Pro tip: Measure one of your t-shirts at home and compare!
A - Length
Measure from the top of the collar to the bottom hem
B - Width
Measure across the chest from armpit to armpit
Size Chart
| Size | Length | Width |
|---|---|---|
| XS | 27" | 16½" |
| S | 28" | 18" |
| M | 29" | 20" |
| L | 30" | 22" |
| XL | 31" | 24" |
| 2XL | 32" | 26" |
| 3XL | 33" | 28" |
| Size | Length | Width |
|---|---|---|
| XS | 69 cm | 42 cm |
| S | 71 cm | 46 cm |
| M | 74 cm | 51 cm |
| L | 76 cm | 56 cm |
| XL | 79 cm | 61 cm |
| 2XL | 81 cm | 66 cm |
| 3XL | 84 cm | 71 cm |